1. Statement of the Technical Field
The inventive arrangements relate to telematic control systems and methods, and more particularly to a single haptic interface and related methods that can be used to control both a vehicle base and a robotic arm coupled to the vehicle base of a robotic system.
2. Description of the Related Art
Robotic systems are growing increasingly common for use in areas in which a human may be subjected to dangerous or otherwise unpleasant work environments. Such applications include explosive ordinance disposal, search and rescue missions, environmental analysis or inspection at toxic sites and the like. These robotic systems are typically controlled remotely and include a vehicle base and a robotic arm mounted onto the vehicle base. The vehicle base is used to bring the robotic arm into the proximity of a target location or target object, and then the target location or target object is inspected, manipulated or both using the robotic arm. Control units for teleoperation of robotic systems can sense control inputs provided by a user. These control inputs can be measured by one or more sensors and converted into corresponding signals that are transmitted to the robotic system to cause it to move in a desired manner in accordance with the transmitted signals. However, these control units are often broken up into a first unit that is used to control the vehicle base, and a second unit that is used to control the robotic arm.
With regards to the vehicle base, control is typically effectuated by way of one or more joysticks or their equivalents, such as button pads or the like. Such input devices are simple to use and understand, but also tend to exhibit coarse control of the vehicle base. For situations in which fine control of the movement of the vehicle base is required, the controller will often include a switch or the like that drops the vehicle base into a low-speed mode; control signals that would otherwise be imprecise at relatively high speeds can thus offer more finely grained control at these reduced speeds. This is, however, inconvenient for the user and, to a degree, requires training and familiarization at two speeds rather than one. By way of another method for controlling the vehicle base, U.S. Pat. No. 6,535,793 discloses a point-and-click navigation system and method.
With regards to the robotic arm, simple user interface systems can provide a separately operable control for each movable joint of a robot or robotic manipulator. More complex systems can include hand controllers (sometimes in the form of a pistol grip), which sense the movement by a user's hand. The hand controller generates one or more control signals which are then used for actuating various motion operations of the robotic arm. The control system of the robotic arm will respond to these control signals by activating certain servo-motors, solenoids, or other devices within the robotic arm to produce the desired action.
Haptic technology or haptics involves tactile feedback provided by a device to a user. The tactile feedback is typically provided by applying forces, vibrations and/or motions to one or more portions of a user interface device. Haptics are sometimes used to enhance remote control devices associated with machines and virtual reality systems. For example, U.S. Pat. No. 5,831,408 to Jacobus et al. discloses that force feedback systems are sometimes used to communicate forces generated on a robotic hand back to a user, through a hand controller. Reference is also drawn to U.S. Pat. Nos. 7,345,672; 4,837,734; 4,893,981 and 5,004,391, which also disclose haptic teleoperation of a robotic arm. For the vehicle base, however, haptic feedback tends to be quite crude, if present at all, and generally involves simply buzzing or vibrating of the housing of the control pad to provide a signal, such as a warning that the vehicle base is in danger of tipping over or the like.
One drawback of prior art teleoperation devices is that they do not permit fine-grained control of both the vehicle base and the robotic arm using the same device. When a single input device is used for both purposes it tends to be very simply in nature, analogous to a gaming input device, and hence cannot make use of gross hand movements of the user. When a more complex controller is used, such a controller is always used to control only the robotic arm, and a separate, simpler device is then used to control the vehicle base. Hence, a user must switch between different input devices, offering different levels and types of precision, degrees of freedom and haptic feedback, when switching between manipulating the robotic arm and driving the vehicle base. Requiring two separate input systems increases system bulk and user training times.